The present invention relates to fiber optic arrays and more particularly to large, matrix configured arrays and the method and tools for making the same. Fiber optics has been the driving force in the communication revolution which has enabled carriers to achieve enormous data throughput. In order to realize the full potential of the technology, fiberoptics will be incorporated into every facet of the integrated electronics, which will then make it possible to fully utilize the enormous bandwidth of the optical fiber with the high speeds of the semiconductor integrated circuitry. To this end, arrays of optical fibers need to be coupled precisely and reliably to semiconductor laser and detector arrays on a chip.
Already, various groups throughout the world have demonstrated feasibility of high-speed optoelectronic VLSI switching and two dimensional fiberoptic arrays for an optical crossbar switch. In 1996, reports were published of achieving approximately + or xe2x88x925 micrometer fiber positional accuracy. In June 1997, Messrs. J. Sherman et al. filed and obtained on May 25, 1999 U.S. Pat. No. 5,907,650 by Fiberguide Industries, Inc. relating to a new method and array achieving at least + or xe2x88x922 micrometer fiber positional accuracy. Although these advances in the art enhance the accuracy and reliability of fiber arrays, they introduce or amplify other technical problems that must be solved to satisfy industry""s need for large number, reliable, high precision, fiber matrix arrays. For example, as the demand for the number of fibers in matrix arrays increases, from 8xc3x978 just a few years ago to the present more than 128xc3x97128, assembly problems arise because of the difficulty in handling and positioning and securing the large number of fibers in the assembly.
A primary object of the present invention is to provide new connector apparatus and methods of assembly that solve the aforementioned problems, provide an efficient and reliable manufacturing method for such large element number arrays and produce such a fiber array connector matrix with highly accurate and reliable fiber placement that is sufficiently robust for further installation and use in the field.
Another primary object of the present invention is to provide such an optical array with enhanced precision compared to the known prior art, which can be effectively and efficiently manufactured, with lower unit costs than currently available products. This is accomplished, according to the principles of the present invention by providing a front mask with fiber seating opening side walls and means for pressing the inserted fiber outer surface against those walls for secure and precise lateral positioning. Each opening can be any suitable shape and bonding material, preferably fills the voids between the fiber and opening walls.
One exemplary embodiment according to the principles of the present invention includes a front mask wafer, a clamping wafer, and a rear wafer mounted to the front face of a suitable housing. Each wafer includes openings of suitable shape, longitudinally aligned and slightly larger than the fiber to allow easy longitudinal insertion. In one example, the openings are generally square or rectangular in shape with the corner-to-corner diameter arranged in a predetermined direction, such as vertically. Once all desired fibers are inserted into all predetermined mask openings, the clamping wafer is moved slightly in the predetermined direction so that its opening upper walls force the respective fiber against the lower walls of the front mask and rear wafer openings. This action presses the fiber in a precise position relative to the front mask-opening array. The clamping wafer is then secured relative to the housing and bonding material is applied as desired. Grinding and polishing the bonding material, fiber tip and front mask surface completes the sub-assembly preparation. Some of the benefits of this method include easy fiber insertion without having to etch or shape the tip to a conical shape although, it does not preclude each pre-shaping. Also, the method accommodates insertion and securing ribbon fibers which are assured of being of the same length in the final assembly.
An alternate embodiment precisely secures the fibers in the array by providing a wafer with unconnected openings that have a transverse dimension slightly smaller than that of the fiber outer diameter. The wafer material defines two sides of each opening which are etched or otherwise shaped into one or two flexible independently movable arms extending away from the opening. The proximal end of each arm is integral with the main wafer body. The arm(s) distal end(s) deflect in response to the fiber insertion causing the fiber to seat against the other two, non-movable sides of the opening. Bonding, polishing, finishing follows all fiber seating. In one embodiment, the opening is square and each of two adjacent sides comprise a flexible arm, and the arms press the fiber into engagement with the other two sides of the square opening.